Locations of neurons in the zebrafish brain that respond to the onset of water flow from head to tail (red), from tail to head (green), or in either direction (blue). Dashed lines show borders of the telencephalon (Telen), optic tectum (OT), and medial octavolateralis nuclei (MON); dotted line shows outline of torus semicircularis (TS). See Vanwalleghem et al. for details.